BP is to hive off its Gulf of Mexico oil spill operation to a separate in-house business to be run by an American in a bid to isolate the "toxic" side of the company and dilute some of the anti-British feeling aimed at chief executive Tony Hayward, the company said today.

The surprise announcement was made during a teleconference with City and Wall Street analysts in which Hayward attempted to shrug off the personal criticism saying words "could not break his bones".

BP has faced mounting anger in the US over the accident on 20 April when the Deepwater Horizon rig blew up and sank with the loss of 11 oil workers' lives.

The Macondo well continues to spew out oil although a containment cap was placed on top of the leak today. Hayward said it would take a further 48 hours to know whether it was successful.

Responsibility for the leaking well and the clean-up strategy will placed in the hands of Bob Dudley, one of the company's most able directors.

Dudley, a US citizen, has been looking for a suitable role in the company since he was thrown out of Moscow in a battle with the Russian shareholders of the TNK-BP joint venture in the middle of 2008.

Hayward said the clean-up business would be run separately by Dudley with his own staff but the finances and budget would come from the main BP group. The BP chief executive said the purpose of the split was to allow Dudley to concentrate on the Gulf problem while he and other directors were not distracted from keeping the main business on track.

Hayward stressed, however, that his priority was sorting out all the wider fallout from the rig disaster and he apologised repeatedly for the loss of lives and ongoing damage to the beaches of the southern United States.

"Everyone at BP is heartbroken by this event, by the loss of life and by the damage to the environment and to the livelihoods of the people of the Gulf coast," he said.

"It should not have happened and we are bound and determined to learn every lesson to try and ensure it never happens again. We will stand by our obligations.

"We will halt this spill and put right the damage that has been done. We will rebuild the confidence of the American people and the world in BP."

The spill has brought verbal attacks on BP from everyone up to Barack Obama, who said yesterday during his third trip to the gulf region: "What I don't want to hear is, when they're spending that kind of money on their shareholders and spending that kind of money on TV advertising, that they're nickeling and diming fishermen or small businesses here in the gulf who are having a hard time."

In the face of such criticism, Hayward insisted that he had a "thick jacket", adding: "They've thrown some words at me, but I'm a Brit. Sticks and stones may break my bones but words will never hurt me."

He denied there was tension between him and BP's new Swedish chairman, Carl-Henric Svanberg, saying both he and the wider board had been extremely supportive.

Svanberg has been accused of keeping himself out of the line of fire but has denied that, saying it was important for the purpose of a clear message that one person took the main role in explaining actions of the company.

Svanberg also ignored demands from two US senators that the company should halt the payments of any dividends to shareholders until the extent of its clean-up liabilities were known.

The chairman said no decision would be taken on future dividends until they had to, but stressed his belief that the company was in good financial shape, indicating it could do both.

He said: "We fully understand the importance of our dividend to our shareholders.

"Future decisions on the quarterly dividend will be made by the board, as they always have been, on the basis of the circumstances at the time."

Hayward's gaffes

"This was not our accident … This was Transocean's rig. Their systems. Their people. Their equipment." 4 May

"The Gulf of Mexico is a big ocean. The amount of oil and dispersant we are putting into it is tiny in relation to the total water volume." 14 May

"No one wants this over more than I do. I would like my life back." 30 May

"So far I'm unscathed ... Sticks and stones may break my bones but words will never hurt me." 4 June